Eltrombopag

ITP is an autoimmune disease in which antiplatelet antibodies accelerate the destruction of platelets. In addition, platelet production can be impaired because the antiplatelet antibodies can also damage megakaryocytes. Although the thrombocytopenia of ITP can be severe, signs of bleeding are usually only minor.
Eltrombopag is an oral, small-molecule, nonpeptide TPO-receptor agonist. It initiates TPO-receptor signaling by interacting with the transmembrane domain of the receptor, thereby inducing proliferation and differentiation of cells in the megakaryocytic lineage. Eltrombopag is the second TPO-receptor agonist to reach the market behind romiplostim (Nplate), a recombinant fusion protein launched in 2008. Both drugs are specifically indicated for the treatment of thrombocytopenia in patients with chronic ITP who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy. Eltrombopag is supplied as the ethanolamine salt (also known as eltrombopag olamine).
The most common adverse reactions associated with eltrombopag were nausea, vomiting, mennorrhagia, myalgia, paresthesia and cataracts. Eltrombopag is derived in five synthetic steps starting from 2-bromo-6-nitroanisole, via Suzuki coupling reaction with 3-carboxyphenylboronic acid to a biphenyl intermediate, followed by cleavage of the methyl ether moiety with hydrobromic acid, and reduction of the nitro group to an amino group under catalytic hydrogenation conditions. Subsequently, the amino group is diazotized with sodium nitrite and hydrochloric acid, and the diazonium intermediate is condensed with 1-(3,4-dimethylphenyl)-3-methyl-2,5-dihydro-1H-pyrazol-5-one to produce eltrombopag.

Orange to Red Solid

Ligand Pharmaceuticals (US)

Eltrombopag (SB-497115-GR, Promacta, Revolade) is a small molecule agonist of the c-mpl (TpoR) receptor with an IC50 of 0.69 μM for the inhibition of hERG K+ channel tail current. In preclinical studies, the compound was shown to interact selectively with

An agonist of the Thrombopoietin (Tpo) receptor, used as treatment for thrombocytopenia.

ChEBI: A hydrazine in which each nitrogen atom is substituted, one by a 3'-carboxy-2-hydroxy[1,1'-biphenyl]-3-yl group and the other by a 1-(3,4-dimethylphenyl)-3-methyl-5-oxo-1,5-dihydro-4H-pyrazol-4-ylidene group. A small molecule agonist of the c-mpl (TpoR) receptor (the physiological target of the hormone thrombopoietin), it has been developed as a medication for conditions that lead to thrombocytopenia (abnormally low platelet counts).

Promacta

Thrombopoetin receptor agonist:
Treatment of chronic immune idiopathic thrombocytopenic purpura (ITP)
Chronic hepatitis C associated thrombocytopenia (HCV)
Severe aplastic anaemia

The synthesis of Eltrombopag is as follows:
At room temperature, add 8.02g (20.0mmol) compound of formula V, 3.98g (24.0mmol) 3-carboxyphenylboronic acid, 8.48g (80.0mmol) sodium carbonate, 1.46g (2.0mmol) PdCl2dppf into a 250mL three-necked flask, 80mL ethanol, 65mL water, nitrogen protection, heated to 80, reacted for 10h, cooled to room temperature, added 60mL water, filtered, the filtrate was adjusted to pH 1-2 with 2M hydrochloric acid, a red solid was precipitated, filtered, and the filter cake was ethanol/water ( v/v=1:1, 40mL) beating, filtering, and drying to obtain 7.58g, the yield is 85.8%, and the purity is 99.40%.

Potentially hazardous interactions with other drugs
Ciclosporin: concentration of eltrombopag reduced.
Statins: increased rosuvastatin concentration, may need to reduce rosuvastatin dose.

Mainly hepatically metabolised through cleavage, oxidation by cytochrome P450 isoenzymes CYP1A2 and CYP 2C8 and conjugation with glucuronic acid, glutathione, or cysteine.
Approximately 31% of a dose is eliminated in the urine as metabolites, and about 59% in the faeces (20% unchanged).

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[2] CONNIE L. ERICKSON-MILLER. Preclinical Activity of Eltrombopag (SB-497115), an Oral, Nonpeptide Thrombopoietin Receptor Agonist†‡§[J]. STEM CELLS, 2009, 27 2: 424-430. DOI:10.1634/stemcells.2008-0366
[3] LUIGI J ALVARADO. Eltrombopag maintains human hematopoietic stem and progenitor cells under inflammatory conditions mediated by IFN-γ.[J]. Blood, 2019, 133 19: 2043-2055. DOI:10.1182/blood-2018-11-884486
[4] KACEY L. GUENTHER . Eltrombopag promotes DNA repair in human hematopoietic stem and progenitor cells[J]. Experimental hematology, 2019, 73: Pages 1-6.e6. DOI:10.1016/j.exphem.2019.03.002
[5] EVANGELIA VLACHODIMITROPOULOU. Eltrombopag: a powerful chelator of cellular or extracellular iron(III) alone or combined with a second chelator.[J]. Blood, 2017, 130 17: 1923-1933. DOI:10.1182/blood-2016-10-740241
[6] YUN-RUEI KAO. Thrombopoietin receptor–independent stimulation of hematopoietic stem cells by eltrombopag[J]. Science Translational Medicine, 2018, 10 458. DOI:10.1126/scitranslmed.aas9563